“Hallux valgus” or “hallux abducto valgus” is a common disorder of the forefoot, which is associated with bunion deformity. The term refers to an abnormal slant of the big toe relative to the second toe. It is one of the most common pathologic conditions affecting the foot and toes.
Hallux valgus results from a medial deviation of the first metatarsal bone and lateral deviation and/or rotation of the big toe (hallux), with or without medial soft-tissue enlargement of the first metatarsal head (bunion). In normal feet, the angle between the first and second metatarsal bones (known as the Inter-Metatarsal Angle, or IMA) is typically in the range of 6-9°. In hallux valgus, this angle may increase to more than 12° in moderate cases and more than 16° in severe cases. Treatment of hallux valgus often includes surgical intervention to reduce the inter-metatarsal angle.
A number of surgical devices and techniques have been developed for reduction of the inter-metatarsal angle. For example, U.S. Patent Application Publication 2010/0152752, whose disclosure is incorporated herein by reference, describes a method and apparatus for bunion repair using a suture-passing K-wire. (A K-wire, or Kirschner wire, is a sharpened, smooth metal pin, widely used in orthopedic surgery, which is driven into the bone using a drill.) The K-wire is used to pass a suture through the first and second metatarsal bones. The first and second metatarsals are pushed together to correct the inter-metatarsal angle deformity, and the suture is tied in this position to hold anchor buttons against the bones. Arthrex, Inc. (Naples, Fla.) offers a commercial product of this sort, known as the Mini TightRope, which is also described in U.S. Pat. No. 7,875,058.
PCT International Publication WO 2009/018527 describes a fixation and alignment device for use in orthopedic surgery, for the correction of bone deformities. The device is part of an anchoring system that is said to be suitable for surgical repair of hallux valgus and other conditions. The system is used to anchor two or more sections of bone or other body parts and to align one section relative to another.
PCT International Publication WO 2010/093696 describes devices for treating hallux valgus using dynamic tensioning components or heat shrinkable components to urge two metatarsals together to treat a bone deformity. The dynamic tensioning component exhibits elasticity and has a tensioned state and an untensioned state. In the tensioned state, the component urges first and second anchors, attached to the first and second metatarsal bones, toward each other.